Electrical apparatus



Sept. 20, 1960 H. J. RAUL 2,953,278

ELECTRICAL APPARATUS Filed July 16, 1957 Fig.2 4 2o l 42 {g 36 \\W p\\\\\\\\\\] WITNESSES INVENTOR Harry J. Koul MJ WCM [ATTORNEY United States Patent ELECTRICAL APPARATUS Harry J. Kaul, Sharon, 'Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed July 16, 1957, Ser. No. 672,291

7 Claims. (Cl. 220-67) This invention relates to tanks for electrical apparatus and more particularly to the joining together of the side wall and end members of such tanks.

A problem arises in the opening of the tank of certain types of liquid-filled transformers. Such transformers include those having a welded joint between the side wall of the tank and the end member of the tank at the bottom of the transformer. A fire hazard is present whenever the joint is opened by removing the weld by burning. This fire hazard exists even though most of the insulating liquid is drained from the tank by opening a drain valve since it is practically impossible to completely empty the tank of all insulating liquid. It is therefore desirable to provide a welded joint for transformers of the above type which would substantially eliminate the fire hazard which is present whenever a tank on a transformer of the above type is opened by burning means.

An object of this invention is to provide a new and improved electrical apparatus.

Another object of this invention is to provide a new and improved joint in a tank for electrical apparatus such that the fire hazard will be substantially eliminated when the joint is opened.

Other objects of the invention will, in part, be obvious and will, in part, appear hereinafter.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawing, in which:

Figure 1 is a view partly in elevation and partly in section showing a liquid insulated transformer within a tank;

Fig. 2 is a fragmentary view illustrating how the joint shown in Fig. 1 is made;

Fig. 3 is a fragmentary view illustrating how the joint shown in Fig. 1 is opened; and

Fig. 4 is a fragmentary view of a second embodiment of the joint shown in Fig. 1.

Referring now to the drawing and Fig. l in particular, a transformer tank is shown in which is mounted a transformer core and coil assembly 24 which would be immersed in an insulating liquid. On the top of the transformer tank 10 may be mounted the bushings 22 for accommodating the connection of the transformer windings to a power circuit in a well-known manner. A man hole 26 may also be provided on the top of the transformer tank 10. The core and coil assembly 24 may be supported by the bottom end frame 28. The tank 10 includes a side wall portion 20 and an end member 40 which is supported in this instance by the channel iron 46. A drain valve 44 is provided so that the insulating liquid inside the transformer tank 10 may be removed from the tank 10. The joint between the side wall portion 20 and the end member 40 of the tank 10 comprises a metallic band 34 disposed to follow the periphery of the side wall 20 adjacent to the end member 40, non-inflammable material 38 disposed between the side wall 20 and the band 34, non-inflammable material 42 disposed between the side wall 20 and the end member 40, a first weld 32 joining the band 34 to the side wall 20, and a second weld 36 joining the band 34 to the end member 40. The non-inflammable materials 38 and 42 would preferably be asbestos.

Referring to Fig. 2, the first step in making the joint between the side wall 20 and the end member 40 is illustrated. The band 34 is formed around the periphery of the side wall 20 adjacent to the end member 40 with a quantity of non-inflammable material 38 disposed be secured to the side wall 20 and the band 34, which is attached thereto. The side wall 20 and the band 34 are next lowered onto the end member as shown in Fig. 1. Referring to Fig. 1, the second weld 36 is then made joining the band 34 to the end member 40. The latter method of making the joint between the side wall 20 and the end member 40 would be employed in the manufacture of the tank 10 before the insulating liquid had been put into the transformer tank 10. Therefore, there would be no fire hazard in making the joint between the side wall 20 and the end member 40 in the manner just described.

Referring to Fig. 3, there is illustrated the method by which the joint between the side wall 20 and the end member 40 shown in Fig. l is opened after the transformer tank 10 has been placed in service. It is assumed that the insulating liquid has been drained from the transformer tank 10 by opening the drain valve 44. As previously stated, a fire hazard would still exist in opening a conventional welded joint on a transformer tank because of the residue of oil remaining in the transformer tank 10 even after most of the insulating liquid has been removed by opening the drain valve 44. The first step in opening the joint between the side wall 20 and the end member 40 is to remove the weld 32 by burning. The burning flame cannot reach any residue of insulating oil inside the transformer tank 10 because of the noninflammable materials 38 and 42 which form part of the joint between the side wall 20 and the end member 40. To ensure complete separation of the side wall 20 and the band 34, a small part of the band 34 at the top of the band may also be removed when removing the weld 32. The side wall 20 may then be raised away from the end member 40 and the band 34, as shown in Fig. 3. After opening the joint between the side wall 20 and the end member 40 by the method just described, any irregularities on the side wall 20 adjacent to the end member 40 and on the inside of the band 34 should be removed by grinding. When making a new joint between the side 20 and the end member 40 after the joint has been opened as illustrated in Fig. 3, the first step is to lower the side wall 20 inside the band 34, the original non-inflammable material 38 having been removed and therefore not interfering with the lowering of the side wall 20. The space between the side wall 20 and the band 34 should next be filled with the non-inflammable material 38. The final step in reclosing the joint between the side wall 20 and the end member 40 is to replace the weld 32, as shown in Fig. 1.

Referring to Fig. 4, a joint between the side wall 20 and the end member 40 is illustrated, which may be substituted for the joint shown in Fig. l. The joint shown in Fig. 4 differs from the joint shown in Fig. 1 in that a band 54 is bent inward toward the side wall 20 at the top of the band 54. A weld 52 then joins the band 54 to the side wall '20. The joint shown in Fig. 4 allows greater clearance between the side wall 20 and the portion of the band 54 adjacent to the non-intion betweerr the band 3'4 anr1 the end: member 4(Fin a'= joint embodying the teachings of this invention; It is also to be understood that the non-inflammable materials 38 and 42 may take any of various forms available, such as tape or rope The apparatus embodying the teachings of this invention has the advanta e that a joint incorporating this invention can be opened by' removing a single weld whilethe" fire hazard normally present is substantially eliminated.

Since numerous changes may be made in the abovedescri-bed apparatus and dilierent embodiments of the invention may be made without departing from the spirit thereof, it is intended that all the matter contained in the foregoing description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limitingsense;

I1claim as my invention! 1'. In a tank structure, the combination comprising a side Wall member, an end member, a bandmember disposed about the periphery of said side wall member, noninflammable material disposed between said side wall member and said band member and between said side wall member and said end member, and means for securing said members together.

2. In a tank structure, the combination comprising a side wall member, an end member, a band member disposed about the periphery of said side wall member, noninflammable material disposed between said side wall member and said band member and between said' side wallmember and said end member, and welds securing said members together.

3. In a tank structure having a side wall portion and an end member, a band disposed about the outside periphery of said side wall adjacent to said end member,

4 non-inflammable material disposed between said side wall and said band and between said side wall and said end member, and welds joining said band to said side wall and to said end member.

4. In a tank structure, the combination comprising a side wall member, an end member, a band member disposed about the periphery of said side wall member, asbestos disposed between said side wall member and said band member and between said' side Wall member and said endmember, and welds securing said members togethe'r. I I

5. In a tank structure having a side wall portion and an end member, a band disposed about the outside periphery of said side wall and spaced apart from said side: wall and said end member, non-inflammable material"v disposed between said side wall and said band, a first weld joining said band and said side wall, and a second weld joining said band and said end member.

6". In a tank structure having a side wall portion and an end member, a band disposed about the out-side pe-- riphery of said side wall andspaced apart from said side: wall and said end member, asbestos disposed between said side wall and saidband and between said side wall and said end member, a first Weld joining said band and! said side wall, and asecond weldjoining said band and said end member.

7. In a tank for electrical apparatus, a side wall por tion, an end member, a band disposed about the outside periphery of said side Wall adjacent to said end member, a first layer of non-inflammable material disposed between said band and said side wall, a first welded seamjoining said band to said side wall, a second layer of non inflammable material disposed between said side wall" and said end member, and a second welded seam joiningv saidband to said end member.

References Cited in the file of this patent UNITED STATES PATENTS 2,544,789 Ho'relick et a1. Mar. 13, 1951- 2,587,840 Gruetjen Mar. 4', 1952 2,824,664 French et al. Feb. 25-, 1958 

